The use of focused ion-beam (FIB) microscopes has become common for the preparation of specimens for later analysis in the transmission electron microscope (TEM). The structural artifacts, and even some structural layers, in the device region and interconnect stack of current integrated-circuit devices can be too small to be reliably detected with the secondary electron imaging in a Scanning Electron Microscope (SEM), or FIB, which offers a bulk surface imaging resolution of approximately 3 nm. In comparison, TEM inspection offers much finer image resolution (<0.1 nm), but requires electron-transparent (<100 nm thick) sections of the sample mounted on 3 mm diameter grid disks.
The in-situ lift-out technique is a series of FIB milling and sample-translation steps used to produce a site-specific specimen for later observation in a TEM or other analytical instrument. During in-situ lift-out, a wedge-shaped section (the “lift-out sample”) of material containing the region of interest is first completely excised from the bulk sample, such as a semiconductor wafer or die, using ion-beam milling in the FIB. This lift-out sample is typically 10×5×5 μm in size. Removal of the lift-out sample is then typically performed using an internal nano-manipulator in conjunction with the ion-beam assisted chemical-vapor deposition (CVD) process available with the FIB tool. A suitable nano-manipulator system is the Omniprobe AutoProbe 200™, manufactured by Omniprobe, Inc., of Dallas, Tex. Automated lift-out of a sample is a desirable goal, and an apparatus and method for same is described in the co-pending application cited above. An important aspect of such an automated in-situ lift-out process is the ability to move the nano-manipulator probe tip inside the vacuum chamber of the microscope and detect mechanical contact. The field of application of the disclosure is limited neither to automated lift-out systems, nor to semiconductor samples. Other objects of interest could be micro-mechanical systems, or biological specimens.